Directions:

Preheat the oven to 375. Grease a square
baking pan and set aside. In a mixing bowl, cream
together the butter, sugars and vanilla until fluffy. Add the egg and
mix. Blend in the flour, baking soda and salt, and mix well. Spread
evenly in the pan. Sprinkle with the chips. Bake for 3 minutes, then
remove from the oven and run a knife through the blondies in a zigzag
pattern to make a nice marble swirl. Return to the oven and bake for
15-20 minutes, or until golden brown. Let cool and then cut into
squares.

When doing a double batch (which is what I made) I would recommend using a 15"x10" pan because I used a 9"x13" and the edges got really done since I had to bake it so long to get the center done. The edges were edible -they weren't burnt, but the middle was just WAY better!!